Table of Contents

Component Description

Urinary Polycyclic Aromatic Hydrocarbons (PAHs)

PAHs constitute a group of chemicals which are formed during the incomplete combustion of coal, oil and gas, garbage, and other organic substances. In general, people are exposed to mixtures of PAHs, and the sources are widespread, including vehicle exhausts, asphalt, coal tar, wild fires, agricultural burning, charbroiled foods, and tobacco smoke. PAHs enter the body quickly and easily by all routes of exposure and are readily and predominantly metabolized to hydroxylated metabolites and glucuronide metabolites. These compounds require metabolic activation in order to interact with cellular macromolecules. Measurement of urinary metabolites indicates exposure to the parent PAHs. Although background ranges of PAHs in air and water are known, less is known about PAH background levels in humans.

Eligible Sample

Participants aged 6 years and older who met the subsample requirements.

Description of Laboratory Methodology

The specific analytes measured in this method are monohydroxy-PAH (OH-PAH). The procedure involves enzymatic hydrolysis of urine, extraction, derivatization and analysis using capillary gas chromatog-raphy combined with high resolution mass spectrometry (GC-HRMS). This method uses isotope dilution with carbon-13 labeled internal standards. Ions from each analyte and each carbon-13 labeled internal standard are monitored, and the abundances of each ion are measured. The ratios of these ions are used as criteria for evaluating the data. By evaluating these analytes in urine, a measurement of the body burden from PAH exposure is obtained.

Laboratory Quality Assurance and Monitoring

Urine specimens are processed, stored, and shipped to the Division of Environmental Health Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention for analysis.

Detailed specimen collection and processing instructions are discussed in the NHANES Laboratory/Medical Technologists Procedures Manual (LPM). Vials are stored under appropriate frozen (–20°C) conditions until they are shipped to National Center for Environmental Health for testing.

Mobile Examination Centers (MECs)

Laboratory team performance is monitored using several techniques. NCHS and contract consultants use a structured quality assurance evaluation during unscheduled visits to evaluate both the quality of the laboratory work and the quality-control procedures. Each laboratory staff person is observed for equipment operation, specimen collection and preparation; testing procedures and constructive feedback are given to each staff. Formal retraining sessions are conducted annually to ensure that required skill levels were maintained.

The NHANES QA/QC protocols meet the 1988 Clinical Laboratory Improvement Act mandates. Detailed QA/QC instructions are discussed in the NHANES LPM.

Analytical Laboratories

NHANES uses several methods to monitor the quality of the analyses performed by the laboratories. NCEH developed and distributed a quality control protocol for all the laboratories which outlined the Westgard rules used when running NHANES specimens. Summary statistics for each control pool, QC graphs, and any special considerations are submitted to NCHS. NCHS reviewed the data for trends or shifts. The laboratories are required to explain any identified areas of concern.

All QC procedures recommended by the manufacturers were followed. Reported results for all assays meet the Division of Laboratory Science’s quality control and quality assurance performance criteria for accuracy and precision (similar to specifications outlined by Westgard 1981).

Analytic Notes

Subsample weights

Measures of urinary PAHs were measured in a one third subsample of persons 6 years and over. Special sample weights are required to analyze these data properly. Specific sample weights for this subsample are included in this data file and should be used when analyzing these data.

Variance estimation

The analysis of NHANES  laboratory data must be conducted with the key survey design and basic demographic variables. The NHANES Demographic Data File contains demographic and sample design variables. The recommended procedure for variance estimation requires use of stratum and PSU variables (SDMVSTRA and SDMVPSU, respectively) in the demographic data file.

Links to NHANES Data Files

This laboratory data file can be linked to the other NHANES data files using the unique survey participant identifier SEQN.

Detection Limits

The detection limits were constant for all but four of the analytes in the data set. Two variables are provided for each of these analytes. The variable named URD___LC indicates whether the result was below the limit of detection. There are two values: “0” and “1”. “0” means that the result was at or above the limit of detection. “1” indicates that the result was below the limit of detection. The other variable named URX___ provides the analytic result for that analyte. In cases, where the result was below the limit of detection, the value for that variable is the detection limit divided by the square root of two.

For URXPO2,and URXP06 variables in cases where the result was below the limit of detection, the value for that variable is the detection limit divided by the square root of two.

Please refer to the Analytic Guidelines for further details on the use of sample weights and other analytic issues.

References

Codebook and Frequencies

SEQN - Respondent sequence number

Variable Name:
SEQN
SAS Label:
Respondent sequence number
English Text:
Respondent sequence number.
Target:
Both males and females 6 YEARS - 150 YEARS

WTSB2YR - Environmental B 2 year weights

Variable Name:
WTSB2YR
SAS Label:
Environmental B 2 year weights
English Text:
Environmental B 2 year weights
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 533131.16757 Range of Values 2718 2718
. Missing 0 2718

URXP01 - 1-hydroxynaphthalene (ng/L)

Variable Name:
URXP01
SAS Label:
1-hydroxynaphthalene (ng/L)
English Text:
1-hydroxynaphthalene (ng/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
31.6 to 6150664.6 Range of Values 2496 2496
. Missing 222 2718

URDP01LC - 1-hydroxynaphthalene comment code

Variable Name:
URDP01LC
SAS Label:
1-hydroxynaphthalene comment code
English Text:
1-hydroxynaphthalene comment code
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2495 2495
1 Below lower detection limit 1 2496
. Missing 222 2718

URXP02 - 2-hydroxynaphthalene (ng/L)

Variable Name:
URXP02
SAS Label:
2-hydroxynaphthalene (ng/L)
English Text:
2-hydroxynaphthalene (ng/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
59.4 to 268104.4 Range of Values 2531 2531
. Missing 187 2718

URDP02LC - 2-hydroxynaphthalene comment code

Variable Name:
URDP02LC
SAS Label:
2-hydroxynaphthalene comment code
English Text:
2-hydroxynaphthalene comment code
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2530 2530
1 below lower detection limit 1 2531
. Missing 187 2718

URXP03 - 3-hydroxyfluorene (ng/L)

Variable Name:
URXP03
SAS Label:
3-hydroxyfluorene (ng/L)
English Text:
3-hydroxyfluorene (ng/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
3.5 to 8784 Range of Values 2581 2581
. Missing 137 2718

URDP03LC - 3-hydroxyfluorene comment code

Variable Name:
URDP03LC
SAS Label:
3-hydroxyfluorene comment code
English Text:
3-hydroxyfluorene comment code
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2577 2577
1 Below lower detection limit 4 2581
. Missing 137 2718

URXP04 - 2-hydroxyfluorene (ng/L)

Variable Name:
URXP04
SAS Label:
2-hydroxyfluorene (ng/L)
English Text:
2-hydroxyfluorene (ng/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
7.1 to 21271.3 Range of Values 2582 2582
. Missing 136 2718

URDP04LC - 2-hydroxyfluorene comment code

Variable Name:
URDP04LC
SAS Label:
2-hydroxyfluorene comment code
English Text:
2-hydroxyfluorene comment code
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2581 2581
1 Below lower detection limit 1 2582
. Missing 136 2718

URXP05 - 3-hydroxyphenanthrene (ng/L)

Variable Name:
URXP05
SAS Label:
3-hydroxyphenanthrene (ng/L)
English Text:
3-hydroxyphenanthrene (ng/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
3.5 to 6344.4 Range of Values 2601 2601
. Missing 117 2718

URDP05LC - 3-hydroxyphenanthrene comment code

Variable Name:
URDP05LC
SAS Label:
3-hydroxyphenanthrene comment code
English Text:
3-hydroxyphenanthrene comment code
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2598 2598
1 Below lower detection limit 3 2601
. Missing 117 2718

URXP06 - 1-hydroxyphenanthrene (ng/L)

Variable Name:
URXP06
SAS Label:
1-hydroxyphenanthrene (ng/L)
English Text:
1-hydroxyphenanthrene (ng/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
5.5 to 6330.3 Range of Values 2608 2608
. Missing 110 2718

URDP06LC - 1-hydroxyphenanthrene comment code

Variable Name:
URDP06LC
SAS Label:
1-hydroxyphenanthrene comment code
English Text:
1-hydroxyphenanthrene comment code
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2608 2608
1 Below lower detection limit 0 2608
. Missing 110 2718

URXP07 - 2-hydroxyphenanthrene (ng/L)

Variable Name:
URXP07
SAS Label:
2-hydroxyphenanthrene (ng/L)
English Text:
2-hydroxyphenanthrene (ng/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
3.5 to 4540.8 Range of Values 2572 2572
. Missing 146 2718

URDP07LC - 2-hydroxyphenanthrene comment code

Variable Name:
URDP07LC
SAS Label:
2-hydroxyphenanthrene comment code
English Text:
2-hydroxyphenanthrene comment code
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2561 2561
1 Below lower detection limit 11 2572
. Missing 146 2718

URXP10 - 1-hydroxypyrene (ng/L)

Variable Name:
URXP10
SAS Label:
1-hydroxypyrene (ng/L)
English Text:
1-hydroxypyrene (ng/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
3.5 to 8685.6 Range of Values 2581 2581
. Missing 137 2718

URDP10LC - 1-hydroxypyrene comment code

Variable Name:
URDP10LC
SAS Label:
1-hydroxypyrene comment code
English Text:
1-hydroxypyrene comment code
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2569 2569
1 Below lower detection limit 12 2581
. Missing 137 2718

URXP17 - 9-hydroxyfluorene (ng/L)

Variable Name:
URXP17
SAS Label:
9-hydroxyfluorene (ng/L)
English Text:
9-hydroxyfluorene (ng/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
12.9 to 65656.6 Range of Values 2608 2608
. Missing 110 2718

URDP17LC - 9-hydroxyfluorene comment code

Variable Name:
URDP17LC
SAS Label:
9-hydroxyfluorene comment code
English Text:
9-hydroxyfluorene comment code
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2608 2608
1 Below lower detection limit 0 2608
. Missing 110 2718

URXUCR - Urinary creatinine

Variable Name:
URXUCR
SAS Label:
Urinary creatinine
English Text:
Urinary creatinine
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
5 to 490 Range of Values 2625 2625
. Missing 93 2718